Safety, or excess flow shut-off, valve assemblies are used to prevent uncontrolled (excess) fluid flow resulting from a break in a conduit, such as a flexible conduit connecting a filter system to faucet or a water source. U.S. Pat. No. 3,735,777 discloses an automatic shut-off valve for use with household appliances to prevent the release of water due to a hose connection becoming loose or breaking. The need to prevent uncontrolled excess flow has also been recognized in applications other than water systems. U.S. Pat. No. 5,215,178, for example, discloses a rapid acting safety valve for preventing leakages resulting from failure of a pressurized hydraulic line. In both cases, the valves allow normal flow but automatically close to terminate flow when the flow through the valve becomes excessive, as would occur upon the failure of a hose connection. If excess flow occurs, a valve flapper or piston moves against the force of a spring to close against a valve seat.
A rapid acting shutoff such as disclosed in U.S. Pat. No. 5,215,178 would be subject to premature nuisance shutoff if used to supply a flexible connector in a household water system. In a water system, air can be present in the piping system. A flow surge can occur when air flows through a faucet or toilet fill valve supplied from a flexible connector. A rapid acting shutoff could close in response to such a surge, disabling the supplied appliance until the shutoff condition is corrected by reopening the shutoff device. The valve disclosed in U.S. Pat. No. 3,735,777 includes a damping mechanism to prevent premature nuisance shutoff. An excess flow shut-off valve disclosed in U.S. Pat. Application Publication No.: US 2004/0221893 A1 also includes a damping mechanism to prevent premature nuisance shutoff. In each case, however, these valves must be disconnected to relieve pressure in order to be reset after the failure of a flexible connector. In addition, these valves do not include a reset function for resetting the shut-off mechanism and for allowing excess flow to pass through the valve.
What is still desired is a new and improved safety valve assembly. Among other advantages and benefits, the new and improved safety valve assembly will preferably include a reset mechanism that allows manual opening (“reset”) of the valve. Manual operation of the safety valve assembly, for example, beneficially allows the valve assembly to be reset without first being disconnected from a fluid conduit. Manual operation also allows the safety valve assembly to be held open during excess flow. The new and improved safety valve assembly will preferably also include a set mechanism that causes the valve assembly to be manually closed (“set”). This manual operation allows the valve assembly to be closed if desired even when there is no excess flow.